Bruce had been listed as questionable after rolling his troublesome ankle during Tuesday's practice. Sources said if it was a playoff game, the 49ers likely would have played Bruce, who hasn't missed a game this season despite his ankle issues.
First-round draft pick Michael Crabtree replaced Bruce in the 49ers' starting lineup, but Jason Hill and Josh Morgan also are expected to see more playing time. Other players inactive for San Francisco are defensive backs Nate Clements and Keith Smith; offensive linemen Cody Wallace and Joe Staley; running back Glen Coffee and defensive lineman Demetric Evans. Nate Davis was the listed as third quarterback.
The Bears will be without starting safety Al Afalava, who has a shoulder injury. The other players inactive for Chicago are wide receiver Juaquin Iglesias, running back Garrett Wolfe, safety Kevin Payne, linebacker Pisa Tinoisamoa, offensive lineman Lance Louis, and defensive lineman Matt Toeaina and Jarron Gilbert.
The Associated Press contributed to this report.